diff --git a/apps/ai-game-creator-shell/tests/appSurface/chat-composer.suite.ts b/apps/ai-game-creator-shell/tests/appSurface/chat-composer.suite.ts
index 973df9365..3d875e617 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/chat-composer.suite.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/chat-composer.suite.ts
@@ -21,6 +21,7 @@ import {
   createProjectChatRuntimeHarness,
   expect,
   fireEvent,
+  installTauriRuntime,
   it,
   pickProjectFromLauncher,
   React,
@@ -40,19 +41,6 @@ type InvokeOverrides = Record<
   (args: Record<string, unknown> | undefined) => unknown
 >;
 
-/**
- * 安装测试用 Tauri 替身。
- *
- * `vi.fn` 的返回类型是固定签名，装不进 `window.__TAURI__` 声明的泛型签名（invoke/listen 都是
- * 泛型函数），这里在装入点整体显式转换，行为与直接赋值一致。
- */
-function installTauriRuntime(runtime: {
-  core: { invoke: unknown };
-  event?: { listen: unknown };
-}) {
-  window.__TAURI__ = runtime as unknown as Window['__TAURI__'];
-}
-
 function gameCreatorConfigView(reasoningEffort: string) {
   return {
     path: '/tmp/chat-composer-config.json',
diff --git a/apps/ai-game-creator-shell/tests/appSurface/design-agent.suite.ts b/apps/ai-game-creator-shell/tests/appSurface/design-agent.suite.ts
index a7b4c6a5a..4ff242c1f 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/design-agent.suite.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/design-agent.suite.ts
@@ -6,6 +6,7 @@ import {
   createProjectChatRuntimeHarness,
   expect,
   fireEvent,
+  installTauriRuntime,
   it,
   React,
   render,
@@ -17,16 +18,13 @@ import {
 type ChatRuntimeHarness = ReturnType<typeof createProjectChatRuntimeHarness>;
 
 /**
- * 安装测试用 Tauri 替身。
- *
- * harness 的 invoke/listen 是 `vi.fn` 的固定签名，装不进 `window.__TAURI__` 声明的泛型签名
- * （invoke/listen 都是泛型函数），这里在装入点整体显式转换，行为与直接赋值一致。
+ * 把夹具的 invoke / listen 装进 `window.__TAURI__`：转换点只有 harness.installTauriRuntime 一处。
  */
-function installTauriRuntime(harness: ChatRuntimeHarness) {
-  window.__TAURI__ = {
+function installChatRuntime(harness: ChatRuntimeHarness) {
+  installTauriRuntime({
     core: { invoke: harness.invoke },
     event: { listen: harness.listen },
-  } as unknown as Window['__TAURI__'];
+  });
 }
 
 /**
@@ -50,7 +48,7 @@ const AppComponent = App as React.ComponentType<
 function renderDesignAgent(
   harness: ReturnType<typeof createProjectChatRuntimeHarness>,
 ) {
-  installTauriRuntime(harness);
+  installChatRuntime(harness);
   window.history.pushState({}, '', '/');
   return render(
     React.createElement(AppComponent, {
@@ -401,7 +399,7 @@ export function registerDesignAgentSurfaceTests() {
         ],
       },
     });
-    installTauriRuntime(harness);
+    installChatRuntime(harness);
     window.history.pushState({}, '', '/');
     render(
       React.createElement(AppComponent, {
@@ -765,7 +763,7 @@ export function registerDesignAgentSurfaceTests() {
     const harness = createProjectChatRuntimeHarness({
       designAgentView: designApprovalView(),
     });
-    installTauriRuntime(harness);
+    installChatRuntime(harness);
     window.history.pushState({}, '', '/');
     render(
       React.createElement(AppComponent, {
@@ -808,7 +806,7 @@ export function registerDesignAgentSurfaceTests() {
         },
       },
     });
-    installTauriRuntime(harness);
+    installChatRuntime(harness);
     window.history.pushState({}, '', '/');
     render(
       React.createElement(AppComponent, {
@@ -843,7 +841,7 @@ export function registerDesignAgentSurfaceTests() {
       designAgentView: designConversationView(),
       designAgentContinueView: designConversationView(),
     });
-    installTauriRuntime(harness);
+    installChatRuntime(harness);
     window.history.pushState({}, '', '/');
     render(
       React.createElement(AppComponent, {
@@ -910,7 +908,7 @@ export function registerDesignAgentSurfaceTests() {
     const harness = createProjectChatRuntimeHarness({
       designAgentView: designHistoryView(),
     });
-    installTauriRuntime(harness);
+    installChatRuntime(harness);
     window.history.pushState({}, '', '/');
     render(
       React.createElement(AppComponent, {
diff --git a/apps/ai-game-creator-shell/tests/appSurface/harness.ts b/apps/ai-game-creator-shell/tests/appSurface/harness.ts
index 85f623c6c..1470cb338 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/harness.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/harness.ts
@@ -935,6 +935,33 @@ function createProjectChatRuntimeHarness({
   };
 }
 
+/**
+ * 安装测试用 Tauri 替身。
+ *
+ * `vi.fn` 与各夹具的 invoke / listen 是固定签名，装不进 `window.__TAURI__` 声明的泛型签名
+ * （两者都是泛型函数），这里把唯一的装入点收在 harness，整体显式转换，行为与直接赋值一致。
+ *
+ * 参数用「可调用」下界而不是 `unknown`：非函数的误装（字符串、undefined）会在编译期被挡下，
+ * 同时不与各夹具更具体的 mock 签名冲突；`core` / `event` 都可缺省，只装 invoke 的用例
+ * 不需要伪造 event。
+ */
+export function installTauriRuntime(runtime: {
+  core?: {
+    invoke?: (
+      command: string,
+      args?: Record<string, unknown>,
+    ) => Promise<unknown>;
+  };
+  event?: {
+    listen?: (
+      event: string,
+      handler: (event: { payload: unknown }) => void,
+    ) => Promise<() => void>;
+  };
+}) {
+  window.__TAURI__ = runtime as unknown as Window['__TAURI__'];
+}
+
 export function installResizeObserverStub() {
   let observerCount = 0;
   let observerDisconnected = false;
diff --git a/apps/ai-game-creator-shell/tests/appSurface/project-conversation.suite.ts b/apps/ai-game-creator-shell/tests/appSurface/project-conversation.suite.ts
index 713ce074f..1b13530fd 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/project-conversation.suite.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/project-conversation.suite.ts
@@ -10,6 +10,7 @@ import {
   emptyProjectPolicy,
   expect,
   fireEvent,
+  installTauriRuntime,
   it,
   mockRoleAgentReply,
   renderAppAt,
@@ -20,19 +21,6 @@ import {
   within,
 } from './harness';
 
-/**
- * 安装测试用 Tauri 替身。
- *
- * `vi.fn` 的返回类型是固定签名，装不进 `window.__TAURI__` 声明的泛型签名（invoke/listen 都是
- * 泛型函数），这里在装入点整体显式转换，行为与直接赋值一致。
- */
-function installTauriRuntime(runtime: {
-  core: { invoke: unknown };
-  event?: { listen: unknown };
-}) {
-  window.__TAURI__ = runtime as unknown as Window['__TAURI__'];
-}
-
 export function registerProjectConversationTests() {
   it('splits structured rejections by variant and never by copy', () => {
     // 入队失败是**结构化**载荷：分流只看 `instanceof` 与 `error.type`，文案不参与任何判断，
diff --git a/apps/ai-game-creator-shell/tests/appSurface/project-development.suite.ts b/apps/ai-game-creator-shell/tests/appSurface/project-development.suite.ts
index 57909fb75..0304c4567 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/project-development.suite.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/project-development.suite.ts
@@ -38,6 +38,7 @@ import {
   fireEvent,
   getResourceSelectButton,
   installResizeObserverStub,
+  installTauriRuntime,
   it,
   openResourceFilterPanel,
   ProjectDevelopmentView,
@@ -52,17 +53,6 @@ import {
   within,
 } from './harness';
 
-/**
- * 安装测试用 Tauri 替身。
- *
- * `vi.fn` 的返回类型是固定签名，装不进 `window.__TAURI__` 声明的泛型签名（invoke 是泛型函数），
- * 这里在装入点整体显式转换，行为与直接赋值一致。
- */
-function installTauriRuntime(runtime: { core: { invoke: unknown } }) {
-  // `vi.fn` 固定签名装不进 `window.__TAURI__` 的泛型签名，这里显式转换，运行时行为不变。
-  window.__TAURI__ = runtime as unknown as Window['__TAURI__'];
-}
-
 /**
  * 历史夹具沿用的旧 kind 字面量（如 `design-document` / `game-code`）已不在当前
  * `GameCreationAppAssetKind` 联合里；这些用例依赖未识别 kind 落「待归类」的运行时语义，
diff --git a/apps/ai-game-creator-shell/tests/appSurface/runtime-settings.suite.ts b/apps/ai-game-creator-shell/tests/appSurface/runtime-settings.suite.ts
index 19da5e36c..c972a52bc 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/runtime-settings.suite.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/runtime-settings.suite.ts
@@ -11,6 +11,7 @@ import {
   fireEvent,
   GAME_CREATION_AGENT_RUN_SCHEMA_VERSION,
   type GameCreationAgentRunTrace,
+  installTauriRuntime,
   it,
   renderLauncherAt,
   screen,
@@ -19,16 +20,6 @@ import {
   within,
 } from './harness';
 
-/**
- * 安装测试用 Tauri invoke 替身。
- *
- * `vi.fn` 的返回类型是固定签名，装不进 `window.__TAURI__` 声明的泛型签名（invoke 是泛型
- * 函数），这里在装入点整体显式转换，行为与直接赋值一致。
- */
-function installTauriRuntime(runtime: { core: { invoke: unknown } }) {
-  window.__TAURI__ = runtime as unknown as Window['__TAURI__'];
-}
-
 export function registerAgentStatusDerivationTests() {
   it('keeps fixed overlays below the in-page window title bar', () => {
     const styles = fs.readFileSync(